1. Field of the Invention
The present invention relates to device verification, and, more particularly, to device verification using printed patterns and the optical sensing thereof.
2. Description of the Related Art
Numerous attempts have been made to provide device verification in printing systems. Some such systems include, for example, the use of encryption/decryption, or identification cards, to ensure that an item is authorized to be used or that a particular person is authorized to use the printing system. Such systems, however, typically cannot prevent circumvention of system integrity through the installation of intrusive hardware.
What is needed in the art is a device verification method that reduces the possibility of a successful circumvention of system integrity by intrusive hardware.
The present invention provides device verification methods that reduce the possibility of a successful circumvention of system integrity by intrusive hardware.
The invention, in one form thereof, is directed to a device verification method. The method includes the steps of providing a device including a memory and a print pattern generator communicatively coupled to the memory, the print pattern generator generating image data based at least in part on a first value actually stored in a first memory location in the memory; printing the image data to produce a printed verification pattern; scanning the printed verification pattern to generate a verification value; reading a memorized value purportedly stored in the first memory location of the memory; comparing the memorized value with the verification value; and evaluating the device based on a result of the comparing step.
In another form thereof, the invention is directed to a device verification method including the steps of providing a device including a memory and a print pattern generator communicatively coupled to the memory, the memory including a plurality of memory locations for storing a corresponding plurality of data values, the print pattern generator generating image data based at least in part on the plurality of data values actually stored in the memory; printing the image data to produce a printed verification pattern; scanning the verification pattern to generate verification data; reading memorized values purportedly stored in the plurality of memory locations of the memory; comparing the memorized values with the verification data; and evaluating the device based on a result of the comparing step.
In still another form thereof, the invention is directed to a device verification method including the steps of providing a device including a memory and a print pattern generator communicatively coupled to the memory, the memory including a plurality of memory locations; printing image data to produce a printed verification pattern, the verification pattern including a plurality of areas, each area of the plurality of areas having a corresponding density that is varied in accordance with each memory location of the plurality of memory locations; scanning the verification pattern to generate verification data; reading memorized values purportedly stored in the plurality of memory locations of the memory; comparing the memorized values with the verification data; and determining whether the memorized values are valid.
An advantage of the present invention is that the possibility of a successful circumvention of system integrity by intrusive hardware is reduced.
Another advantage is the device verification is applicable to both a circuit containing memory to be verified, as well as the device to which the circuit is attached, such as a supply item for an imaging system.